1. Field Of The Invention
This invention relates to a roll monitor sled which is used to locate improperly positioned or bent rolls in a continuous caster machine and more particularly to an improved system to handle the data from the roll monitor sled concerning the rolls of the continuous caster machine.
2. Background Information
A conventional curved or straight rack continuous caster machine includes a frame and a plurality of opposed rolls journalled in the frame for guiding and confining a casting as its core continues to solidify.
A curved roll-rack includes top and bottom rolls which guide a casting as its direction of travel changes from substantially vertical to horizontal. A curved roll-rack usually defines an arcuate path of travel of a radius of at least about 30 feet. The gap between the work-engaging faces of the roll-pairs depends on the thickness of the casting. Consequently a curved roll-rack is a massive mechanism, yet it is important that its rolls are all straight and positioned accurately. The work-engaging faces of the top and bottom rolls of each pair should lie accurately on two predetermined arcs. In either a straight or curved roll-rack the gaps between the work-engaging faces of each roll-pair should be equal within small tolerances. Any rolls which are bent or not positioned properly may either become overloaded and hence subject to early failure, or else they do no effectively confine the casting.
In most continuous-casting installations the gaps between roll faces are measured manually and the rolls are adjusted with shims only while the casting machine is down for scheduled maintenance, ideally about one turn a week. Measuring and adjusting the roll gaps manually are awkward operations, often done inaccurately and can lead to severe quality problems. An improperly gapped roll-pair may go unnoticed until the next scheduled maintenance unless an actual failure occurs.
U.S. Pat. No. Re. 30,075, discloses a method and apparatus for locating improperly positioned or bent rolls. The apparatus consists of a roll gap sled comprising a housing movable along the path of travel of a workpiece in the continuous caster, a plurality of gap sensors including heads carried by the housing to contact the work-engaging faces of the individual roll-pairs successively and transducer means connected with the heads to transmit signals representative of the measurement of the gaps between the work-engaging faces of each roll-pair contacted by the heads. The transmitted signals are sent to a recorder mounted on the sled for subsequent analysis to determine the roll gap. This patent also discloses means for measuring the angle of the successive roll-pairs.
U.S. Pat. No. 4,903,750, which is expressly incorporated by reference herein also discloses a roll gap sled. This sled has five gap sensors and two angle sensors. The sled bears against the rolls by means of "spring packs" which are provided on separate portions of the sled.
It is known to transmit the transducer output from the sensors to an analog to digital converter on-board the sled. All of the transducer output is digitized, and sent to an off-line host computer by a dumb radio link. The digitized analog is then reconverted to analog for recording on a chart recorder.
One of the disadvantages with a dumb radio link are that all of the digitized analog is sent to the host computer, thus much extraneous data, such as when the sensors are between rolls in the continuous caster machine, is created. In addition, transmission quality can effect the data sent and received which can lead to errors in roll gap and angle measurement. Finally, current technology is limited to eight digital bits which is insufficient for angle resolution without additional instruments.
There remains a need for a roll gap sled with an improved data handling system. This roll gap sled should give information immediately concerning the roll gap measurements, angle measurements and peak detection and this information should be accurate and presented to the user in an easy to interpret fashion.